D vs a stranger and the prominent and differential role of AG-490 site psychological distress individually and at the dyadic level in moderating the neural response. This study confirms the P2 and slow wave responses as reliable neural responses for friend rejection in middle childhood. Our previous work with stranger exclusion in Cyberball and ERPs (Crowley et al., 2009b, 2010) did not identify P2 responses for rejection events. Potentially, the presence of known others and their higher salience more strongly engages BX795 chemical information attention mechanisms in the frontal region as indexed by P2. The direction of the effect observed on ERP appears to be specific to the type of the relationship, kin vs friend relationship, and the underlying psychological distress. Moreover, not only the individual’s distress but also the combined psychological distress levels in friend pairs affect the brain responses in social exclusion.Limitations and direction for future researchThe issue of sample size frequently arises as a study limitation. In the context of the APIM framework, the number of predictors emerging from a dyadic model compounds sample size issues. In this study, the single examined predictor (psychological distress) led to seven regression terms (Table 4). There are myriad other relevant variables that could be considered within the APIM framework, some of which we suggest below. A sample larger than ours (n ?46) would be needed to explore multiple predictors.Based on our study design, findings are limited to psychological distress, ostracism distress and their individual and dyadic effects on neural response to social exclusion. In the absence of previous work examining social exclusion in the context play with a friend and a stranger, we administered the widely used measure of global ostracism distress (Need Threat for assessing control, belonging, meaningful existence, selfesteem), predicting this self-report would track neural response to rejection events. Our data suggest that psychological distress, but not global ostracism distress tracks neural response when social exclusion involves a friend or a same age/gender stranger. Providing discriminant validity for the psychological distress-rejection event effects, exploratory analysis (see correlation Supplementary Table B) shows that neither psychological distress, nor ostracism distress were related to P2 or slow wave responses when the throws were to the participant in fair play (see Supplementary Figure A for inclusion event ERPs). Two potential factors come to mind that may have contributed to the lack of findings for ostracism distress in this study. First, the measure of global distress does not distinguish between thoughts and emotions about the friend and the thoughts and emotions about the stranger. Clearly our neural response data show that response to friend and stranger are distinguishable. Second, the type of measure could reflect the differential cognitions and emotions that a participant might have for the friend and stranger, respectively. For instance, it could be that factors such as trust and betrayal are more relevant for understanding social exclusion in the context of a friendship. For instance, betrayal of friendship, as in violation of friendship expectations, is associated with increase in negative emotions especially differentially among boys and girls (MacEvoy and Asher, 2012). On the other hand, issues of jealousy, surveillance behavior (Lavallee and Parker, 2009) and interpersonal t.D vs a stranger and the prominent and differential role of psychological distress individually and at the dyadic level in moderating the neural response. This study confirms the P2 and slow wave responses as reliable neural responses for friend rejection in middle childhood. Our previous work with stranger exclusion in Cyberball and ERPs (Crowley et al., 2009b, 2010) did not identify P2 responses for rejection events. Potentially, the presence of known others and their higher salience more strongly engages attention mechanisms in the frontal region as indexed by P2. The direction of the effect observed on ERP appears to be specific to the type of the relationship, kin vs friend relationship, and the underlying psychological distress. Moreover, not only the individual’s distress but also the combined psychological distress levels in friend pairs affect the brain responses in social exclusion.Limitations and direction for future researchThe issue of sample size frequently arises as a study limitation. In the context of the APIM framework, the number of predictors emerging from a dyadic model compounds sample size issues. In this study, the single examined predictor (psychological distress) led to seven regression terms (Table 4). There are myriad other relevant variables that could be considered within the APIM framework, some of which we suggest below. A sample larger than ours (n ?46) would be needed to explore multiple predictors.Based on our study design, findings are limited to psychological distress, ostracism distress and their individual and dyadic effects on neural response to social exclusion. In the absence of previous work examining social exclusion in the context play with a friend and a stranger, we administered the widely used measure of global ostracism distress (Need Threat for assessing control, belonging, meaningful existence, selfesteem), predicting this self-report would track neural response to rejection events. Our data suggest that psychological distress, but not global ostracism distress tracks neural response when social exclusion involves a friend or a same age/gender stranger. Providing discriminant validity for the psychological distress-rejection event effects, exploratory analysis (see correlation Supplementary Table B) shows that neither psychological distress, nor ostracism distress were related to P2 or slow wave responses when the throws were to the participant in fair play (see Supplementary Figure A for inclusion event ERPs). Two potential factors come to mind that may have contributed to the lack of findings for ostracism distress in this study. First, the measure of global distress does not distinguish between thoughts and emotions about the friend and the thoughts and emotions about the stranger. Clearly our neural response data show that response to friend and stranger are distinguishable. Second, the type of measure could reflect the differential cognitions and emotions that a participant might have for the friend and stranger, respectively. For instance, it could be that factors such as trust and betrayal are more relevant for understanding social exclusion in the context of a friendship. For instance, betrayal of friendship, as in violation of friendship expectations, is associated with increase in negative emotions especially differentially among boys and girls (MacEvoy and Asher, 2012). On the other hand, issues of jealousy, surveillance behavior (Lavallee and Parker, 2009) and interpersonal t.
